nearestpoint(x, y, m)

NEARESTPOINT - find the nearest value in another vector

IND = NEARESTPOINT(X,Y) finds the value in Y which is the closest to each value in X, so that abs(Xi-Yk) => abs(Xi-Yj) when k is not equal to j.
IND contains the indices of each of these points.
Example:
NEARESTPOINT([1 4 12],[0 3]) -> [1 2 2]
[IND,D] = ... also returns the absolute distances in D,that is D == abs(X - Y(IND))
NEARESTPOINT(X, Y, M) specifies the operation mode M:
1) 'nearest' : default, same as above
2) 'previous': find the points in Y that just precedes a point in X
NEARESTPOINT([1 4 12],[0 3],'previous') -> [1 1 1]
3) 'next' : find the points in Y that directly follow a point in X
NEARESTPOINT([1 4 12],[0 3],'next') -> [2 NaN NaN]

If there is no previous or next point in Y for a point X(i), IND(i)
will be NaN.

X and Y may be unsorted.

This function is quite fast, and especially suited for large arrays with
time data. For instance, X and Y may be the times of two separate events, like simple and complex spike data of a neurophysiological study.
Run NEARESTPOINT('test') to see a test of it's running time